Retail markets have utilized rigid and flexible plastic containers to contain and display perishable and fragile food items both hot and cold, such as sandwiches, salads and bakery items. These traditional roles of plastic packaging are now the minimum expected standards, and the requirements placed on plastic food packaging continue to expand as increasing demands are placed upon it. Presentation, brand presence, consumer desires, added value to enhance commercial competitiveness, differentiation, imagery and psychology has resulted in the design and application of plastic packaging becoming more challenging. Convenience continues to shape the future of packaging, with consumers gravitating toward packaged convenience items that minimize the impact on their behavior forcing packaging manufacturers to include social and environmental considerations into their development process.
Rigid plastic food containers are typically manufactured from Polystyrene, Polypropylene, Polyethylene Terephthalate (PET), Polylactide, Polyvinyl Chloride (PVC), or other rigid polymers. They generally comprise either of two-parts—a tray and lid—or they may be a one-piece construction with a hinge that modifies one portion of the container to act as the tray and the other connected portion to act as a lid. This general configuration of food containers in a large variety of shapes and cross-sections (circular, rectangular, square, and elliptical, etc.) has been available in the marketplace for many years.
However, a limitation or concern has been undisclosed potentially malicious ingress into such containers that can lead to inadvertent or intentional contamination of the contents of the food container. This has created an increased awareness of and demand for tamper-resistant and tamper-evident food packaging systems. Product tampering has been in existence for as long as there have been packaged consumer goods. The causes of tampering are varied but generally take one of two forms: the first is malevolent tampering, and the second is for personal gratification, where one samples a product and puts it back on the shelf and the next customer is unaware of the contamination. Both modes of tampering compromises the safety and quality of food package contents. The costs of tampering are enormous. In addition to the recalling of tampered, as well as un-tampered product, the resulting negative publicity can lead to reduction in revenue and brand equity, with retailers being forced to stop purchasing from one or more products form the affected company or even litigation.
In 1982, Johnson and Johnson (J&J) experienced such a situation when numerous bottles of its Extra-Strength Tylenol capsules had been laced with cyanide. By the end of the crisis, J&J had spent $100 million recalling 31 million bottles, they ceased production of the product and further pursued redesign of its bottles. Seven people died from the ingestion of the cyanide-laced pills. The threat of tampering has been amplified in the wake of the terrorist attack of Sep. 11, 2001. Possible contamination of food product on a potentially larger scale been envisioned.
In the packaging industry, tampering is the interference with the package contents, and the risk of tampering is a phenomenon that we have come to accept as a necessary evil when making purchases. Today, it is impossible to find food packaging that does not have a security feature. Virtually every packaged food product is enclosed or is attached to a tamper-evident or tamper-proof security feature. Tamper-evident means that a package that has undergone tampering will show some readily observable sign that the tampering has taken place; the sign may be audible or visible. It is the opinion of the inventor that in addition to its functions of protecting the product inside against physical and microbiological harm and oxygen ingress, and of providing brand recognition and product differentiation in the marketplace, packaging should also be designed to protect the consumer against tampering, whether deliberate or accidental.
Methods developed and currently used to combat tampering have included bonding the edges of existing packages. The advantage of such an approach is that a barrier against tampering could be achieved without changing the packaging design. Alternatively, addition of clear or printed shrink-wrap over the neck edge joint between the lid and tray or the entire package that keeps the packaging and its contents secure have been used. These methods provide some assurance to the consumer that the product has not been interfered with. Similarly, other attempts developed to combat packaging product tampering include of under-lid barriers (e.g. heat-sealed pop-up lids, glued boxes and tape seals).
A limitation associated with these methods, however, is that they achieve only a low level of tamper-evident packaging. They are either not sufficiently or distinctively visible to the consumer, or they can be return to its original condition with a glue gun and a hair dryer. This further makes disposal of unused sealing material a security issue as unused, intact seals may be used to reseal contaminated product.
It would be advantageous to consumers if there were a simple method that would rapidly indicate if a rigid plastic food package had been interfered with, that is, opened and then re-closed prior to purchase.
As it is extremely difficult to develop product packaging that is regarded as fully tamper-proof, the packaging industry's efforts have been directed to develop solutions that would ensure that any tampering can be clearly visible to the potential consumer. In response to the evolving demands of consumers, retailers continue to seek novel plastic packaging solutions to improve on the safety, convenience and therefore marketability of food product.
As such, the inventors recognizes that greater utility of such rigid plastic containers would be obtained through improved tamper-evident containerization methods and designs to increase the safety to the consumer but yet retains both the functional aspects required from rigid plastic packaging. The present invention fulfills this need.